access modes are mandatory and access modifiers code example

Example 1: access specifiers in Java

In Java, access specifiers are the keywords which are used to define 
the access scope of the method, class, or a variable. 
  In Java, there are four access specifiers.
  
  * Public: The classes, methods, or variables which are defined as public, 
  can be accessed by any class or method.
  * Protected: Protected can be accessed by the class of the same package, 
or by the sub-class of this class, or within the same class.
  * Default: Default are accessible within the package only. 
    By default, all the classes, methods, and variables are of default scope.
  * Private: The private class, methods, or variables defined as private 
    can be accessed within the class only

Example 2: what access modifiers can be used for methods

We can use all access modifiers public, private,protected and default for 
methods.
public : When a method is declared as public it can be accessed
6) In the same class
7) In the same package subclass
8) In the same package nonsubclass
9) In the different package subclass
10) In the different package non subclass.
default : When a method is declared as default, we can access that method in
1) In the same class
2) In the same package subclass
3) In the same package non subclass
We cannot access default access method in
1) Different package subclass
2) Different package non subclass.
protected : When a method is declared as protected it can be accessed
1) With in the same class
2) With in the same package subclass
3) With in the same package non subclass
4) With in different package subclass
It cannot be accessed non subclass in different package.
private : When a method is declared as private it can be accessed only in 
that class.
It cannot be accessed in
1) Same package subclass
2) Same package non subclass
3) Different package subclass
4) Different package non subclas